Though I am a supporter of a free and open standard console format, I don't think that it's likely to happen any time soon. First we need to get through the Age of Updates.
What this means is that the next direction for console manufacturers is clearly one of multiple configurations based on a standardised hardware type rather than trying to make a whole new leap again in 3-4 years. They spend all this time and effort developing their baseline, but rather than just let it sit there and grow old (as has been traditional), what they are doing - and should continue to do - is think like Apple.
That means constant revisions of the baseline product. Xbox 360, for example, could easily run and run with more features, better controllers, more hard drive space, HD-DVD drives and the like while keeping the common features of the console fairly static. PS3 can do likewise. Wii is probably less easily amenable and its not certain whether they have an audience that responds to that sort of constant-upgrade strategy.
Gamers clearly have an appetite for machines. Since 2000, including handhelds, there have been over half a dozen major hardware launches from the GBA SP to the PS3, and stores have become a Byzantine hive of formats with dedicated catalogues. For Microsoft and Sony this should be thought of as good news, because it means that they can tap their customers again, and regularly, perhaps as often as every two years.
Via the joys of eBay and second-hand sales in stores, customers can mitigate costs and be encouraged to upgrade to the new 360, the new PS3, with its shiny new stuff all in. They can also be assured that their old joypads and the like will still work, that the console network can update/patch any compatibility issues that arise, and possibly even transfer important data or download it again.
Of course multiple-configuration development would be more difficult for developers, publishers and QA-ing games, but it's probably absorb-able when traded off against the cost of another full generation shift.
So that's the future then. It's not Xbox 720 and PS4, it's Xbox 361 and PS3.1.
And probably Wii2 somewhere down the line.
Particleblog's comments have moved to The Play Room.